1 /*
2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
3  *
4  * Copyright (C) 2002-2011 Aleph One Ltd.
5  *   for Toby Churchill Ltd and Brightstar Engineering
6  *
7  * Created by Charles Manning <charles@aleph1.co.uk>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include "yaffs_guts.h"
15 #include "yaffs_trace.h"
16 #include "yaffs_yaffs2.h"
17 #include "yaffs_checkptrw.h"
18 #include "yaffs_bitmap.h"
19 #include "yaffs_nand.h"
20 #include "yaffs_getblockinfo.h"
21 #include "yaffs_verify.h"
22 #include "yaffs_attribs.h"
23 #include "yaffs_summary.h"
24 #include <dm/devres.h>
25 
26 /*
27  * Checkpoints are really no benefit on very small partitions.
28  *
29  * To save space on small partitions don't bother with checkpoints unless
30  * the partition is at least this big.
31  */
32 #define YAFFS_CHECKPOINT_MIN_BLOCKS 60
33 #define YAFFS_SMALL_HOLE_THRESHOLD 4
34 
35 /*
36  * Oldest Dirty Sequence Number handling.
37  */
38 
39 /* yaffs_calc_oldest_dirty_seq()
40  * yaffs2_find_oldest_dirty_seq()
41  * Calculate the oldest dirty sequence number if we don't know it.
42  */
yaffs_calc_oldest_dirty_seq(struct yaffs_dev * dev)43 void yaffs_calc_oldest_dirty_seq(struct yaffs_dev *dev)
44 {
45 	int i;
46 	unsigned seq;
47 	unsigned block_no = 0;
48 	struct yaffs_block_info *b;
49 
50 	if (!dev->param.is_yaffs2)
51 		return;
52 
53 	/* Find the oldest dirty sequence number. */
54 	seq = dev->seq_number + 1;
55 	b = dev->block_info;
56 	for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
57 		if (b->block_state == YAFFS_BLOCK_STATE_FULL &&
58 		    (b->pages_in_use - b->soft_del_pages) <
59 		    dev->param.chunks_per_block &&
60 		    b->seq_number < seq) {
61 			seq = b->seq_number;
62 			block_no = i;
63 		}
64 		b++;
65 	}
66 
67 	if (block_no) {
68 		dev->oldest_dirty_seq = seq;
69 		dev->oldest_dirty_block = block_no;
70 	}
71 }
72 
yaffs2_find_oldest_dirty_seq(struct yaffs_dev * dev)73 void yaffs2_find_oldest_dirty_seq(struct yaffs_dev *dev)
74 {
75 	if (!dev->param.is_yaffs2)
76 		return;
77 
78 	if (!dev->oldest_dirty_seq)
79 		yaffs_calc_oldest_dirty_seq(dev);
80 }
81 
82 /*
83  * yaffs_clear_oldest_dirty_seq()
84  * Called when a block is erased or marked bad. (ie. when its seq_number
85  * becomes invalid). If the value matches the oldest then we clear
86  * dev->oldest_dirty_seq to force its recomputation.
87  */
yaffs2_clear_oldest_dirty_seq(struct yaffs_dev * dev,struct yaffs_block_info * bi)88 void yaffs2_clear_oldest_dirty_seq(struct yaffs_dev *dev,
89 				   struct yaffs_block_info *bi)
90 {
91 
92 	if (!dev->param.is_yaffs2)
93 		return;
94 
95 	if (!bi || bi->seq_number == dev->oldest_dirty_seq) {
96 		dev->oldest_dirty_seq = 0;
97 		dev->oldest_dirty_block = 0;
98 	}
99 }
100 
101 /*
102  * yaffs2_update_oldest_dirty_seq()
103  * Update the oldest dirty sequence number whenever we dirty a block.
104  * Only do this if the oldest_dirty_seq is actually being tracked.
105  */
yaffs2_update_oldest_dirty_seq(struct yaffs_dev * dev,unsigned block_no,struct yaffs_block_info * bi)106 void yaffs2_update_oldest_dirty_seq(struct yaffs_dev *dev, unsigned block_no,
107 				    struct yaffs_block_info *bi)
108 {
109 	if (!dev->param.is_yaffs2)
110 		return;
111 
112 	if (dev->oldest_dirty_seq) {
113 		if (dev->oldest_dirty_seq > bi->seq_number) {
114 			dev->oldest_dirty_seq = bi->seq_number;
115 			dev->oldest_dirty_block = block_no;
116 		}
117 	}
118 }
119 
yaffs_block_ok_for_gc(struct yaffs_dev * dev,struct yaffs_block_info * bi)120 int yaffs_block_ok_for_gc(struct yaffs_dev *dev, struct yaffs_block_info *bi)
121 {
122 
123 	if (!dev->param.is_yaffs2)
124 		return 1;	/* disqualification only applies to yaffs2. */
125 
126 	if (!bi->has_shrink_hdr)
127 		return 1;	/* can gc */
128 
129 	yaffs2_find_oldest_dirty_seq(dev);
130 
131 	/* Can't do gc of this block if there are any blocks older than this
132 	 * one that have discarded pages.
133 	 */
134 	return (bi->seq_number <= dev->oldest_dirty_seq);
135 }
136 
137 /*
138  * yaffs2_find_refresh_block()
139  * periodically finds the oldest full block by sequence number for refreshing.
140  * Only for yaffs2.
141  */
yaffs2_find_refresh_block(struct yaffs_dev * dev)142 u32 yaffs2_find_refresh_block(struct yaffs_dev *dev)
143 {
144 	u32 b;
145 	u32 oldest = 0;
146 	u32 oldest_seq = 0;
147 	struct yaffs_block_info *bi;
148 
149 	if (!dev->param.is_yaffs2)
150 		return oldest;
151 
152 	/*
153 	 * If refresh period < 10 then refreshing is disabled.
154 	 */
155 	if (dev->param.refresh_period < 10)
156 		return oldest;
157 
158 	/*
159 	 * Fix broken values.
160 	 */
161 	if (dev->refresh_skip > dev->param.refresh_period)
162 		dev->refresh_skip = dev->param.refresh_period;
163 
164 	if (dev->refresh_skip > 0)
165 		return oldest;
166 
167 	/*
168 	 * Refresh skip is now zero.
169 	 * We'll do a refresh this time around....
170 	 * Update the refresh skip and find the oldest block.
171 	 */
172 	dev->refresh_skip = dev->param.refresh_period;
173 	dev->refresh_count++;
174 	bi = dev->block_info;
175 	for (b = dev->internal_start_block; b <= dev->internal_end_block; b++) {
176 
177 		if (bi->block_state == YAFFS_BLOCK_STATE_FULL) {
178 
179 			if (oldest < 1 || bi->seq_number < oldest_seq) {
180 				oldest = b;
181 				oldest_seq = bi->seq_number;
182 			}
183 		}
184 		bi++;
185 	}
186 
187 	if (oldest > 0) {
188 		yaffs_trace(YAFFS_TRACE_GC,
189 			"GC refresh count %d selected block %d with seq_number %d",
190 			dev->refresh_count, oldest, oldest_seq);
191 	}
192 
193 	return oldest;
194 }
195 
yaffs2_checkpt_required(struct yaffs_dev * dev)196 int yaffs2_checkpt_required(struct yaffs_dev *dev)
197 {
198 	int nblocks;
199 
200 	if (!dev->param.is_yaffs2)
201 		return 0;
202 
203 	nblocks = dev->internal_end_block - dev->internal_start_block + 1;
204 
205 	return !dev->param.skip_checkpt_wr &&
206 	    !dev->read_only && (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
207 }
208 
yaffs_calc_checkpt_blocks_required(struct yaffs_dev * dev)209 int yaffs_calc_checkpt_blocks_required(struct yaffs_dev *dev)
210 {
211 	int retval;
212 	int n_bytes = 0;
213 	int n_blocks;
214 	int dev_blocks;
215 
216 	if (!dev->param.is_yaffs2)
217 		return 0;
218 
219 	if (!dev->checkpoint_blocks_required && yaffs2_checkpt_required(dev)) {
220 		/* Not a valid value so recalculate */
221 		dev_blocks = dev->param.end_block - dev->param.start_block + 1;
222 		n_bytes += sizeof(struct yaffs_checkpt_validity);
223 		n_bytes += sizeof(struct yaffs_checkpt_dev);
224 		n_bytes += dev_blocks * sizeof(struct yaffs_block_info);
225 		n_bytes += dev_blocks * dev->chunk_bit_stride;
226 		n_bytes +=
227 		    (sizeof(struct yaffs_checkpt_obj) + sizeof(u32)) *
228 		    dev->n_obj;
229 		n_bytes += (dev->tnode_size + sizeof(u32)) * dev->n_tnodes;
230 		n_bytes += sizeof(struct yaffs_checkpt_validity);
231 		n_bytes += sizeof(u32);	/* checksum */
232 
233 		/* Round up and add 2 blocks to allow for some bad blocks,
234 		 * so add 3 */
235 
236 		n_blocks =
237 		    (n_bytes /
238 		     (dev->data_bytes_per_chunk *
239 		      dev->param.chunks_per_block)) + 3;
240 
241 		dev->checkpoint_blocks_required = n_blocks;
242 	}
243 
244 	retval = dev->checkpoint_blocks_required - dev->blocks_in_checkpt;
245 	if (retval < 0)
246 		retval = 0;
247 	return retval;
248 }
249 
250 /*--------------------- Checkpointing --------------------*/
251 
yaffs2_wr_checkpt_validity_marker(struct yaffs_dev * dev,int head)252 static int yaffs2_wr_checkpt_validity_marker(struct yaffs_dev *dev, int head)
253 {
254 	struct yaffs_checkpt_validity cp;
255 
256 	memset(&cp, 0, sizeof(cp));
257 
258 	cp.struct_type = sizeof(cp);
259 	cp.magic = YAFFS_MAGIC;
260 	cp.version = YAFFS_CHECKPOINT_VERSION;
261 	cp.head = (head) ? 1 : 0;
262 
263 	return (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp)) ? 1 : 0;
264 }
265 
yaffs2_rd_checkpt_validity_marker(struct yaffs_dev * dev,int head)266 static int yaffs2_rd_checkpt_validity_marker(struct yaffs_dev *dev, int head)
267 {
268 	struct yaffs_checkpt_validity cp;
269 	int ok;
270 
271 	ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
272 
273 	if (ok)
274 		ok = (cp.struct_type == sizeof(cp)) &&
275 		    (cp.magic == YAFFS_MAGIC) &&
276 		    (cp.version == YAFFS_CHECKPOINT_VERSION) &&
277 		    (cp.head == ((head) ? 1 : 0));
278 	return ok ? 1 : 0;
279 }
280 
yaffs2_dev_to_checkpt_dev(struct yaffs_checkpt_dev * cp,struct yaffs_dev * dev)281 static void yaffs2_dev_to_checkpt_dev(struct yaffs_checkpt_dev *cp,
282 				      struct yaffs_dev *dev)
283 {
284 	cp->n_erased_blocks = dev->n_erased_blocks;
285 	cp->alloc_block = dev->alloc_block;
286 	cp->alloc_page = dev->alloc_page;
287 	cp->n_free_chunks = dev->n_free_chunks;
288 
289 	cp->n_deleted_files = dev->n_deleted_files;
290 	cp->n_unlinked_files = dev->n_unlinked_files;
291 	cp->n_bg_deletions = dev->n_bg_deletions;
292 	cp->seq_number = dev->seq_number;
293 
294 }
295 
yaffs_checkpt_dev_to_dev(struct yaffs_dev * dev,struct yaffs_checkpt_dev * cp)296 static void yaffs_checkpt_dev_to_dev(struct yaffs_dev *dev,
297 				     struct yaffs_checkpt_dev *cp)
298 {
299 	dev->n_erased_blocks = cp->n_erased_blocks;
300 	dev->alloc_block = cp->alloc_block;
301 	dev->alloc_page = cp->alloc_page;
302 	dev->n_free_chunks = cp->n_free_chunks;
303 
304 	dev->n_deleted_files = cp->n_deleted_files;
305 	dev->n_unlinked_files = cp->n_unlinked_files;
306 	dev->n_bg_deletions = cp->n_bg_deletions;
307 	dev->seq_number = cp->seq_number;
308 }
309 
yaffs2_wr_checkpt_dev(struct yaffs_dev * dev)310 static int yaffs2_wr_checkpt_dev(struct yaffs_dev *dev)
311 {
312 	struct yaffs_checkpt_dev cp;
313 	u32 n_bytes;
314 	u32 n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
315 	int ok;
316 
317 	/* Write device runtime values */
318 	yaffs2_dev_to_checkpt_dev(&cp, dev);
319 	cp.struct_type = sizeof(cp);
320 
321 	ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
322 	if (!ok)
323 		return 0;
324 
325 	/* Write block info */
326 	n_bytes = n_blocks * sizeof(struct yaffs_block_info);
327 	ok = (yaffs2_checkpt_wr(dev, dev->block_info, n_bytes) == n_bytes);
328 	if (!ok)
329 		return 0;
330 
331 	/* Write chunk bits */
332 	n_bytes = n_blocks * dev->chunk_bit_stride;
333 	ok = (yaffs2_checkpt_wr(dev, dev->chunk_bits, n_bytes) == n_bytes);
334 
335 	return ok ? 1 : 0;
336 }
337 
yaffs2_rd_checkpt_dev(struct yaffs_dev * dev)338 static int yaffs2_rd_checkpt_dev(struct yaffs_dev *dev)
339 {
340 	struct yaffs_checkpt_dev cp;
341 	u32 n_bytes;
342 	u32 n_blocks =
343 	    (dev->internal_end_block - dev->internal_start_block + 1);
344 	int ok;
345 
346 	ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
347 	if (!ok)
348 		return 0;
349 
350 	if (cp.struct_type != sizeof(cp))
351 		return 0;
352 
353 	yaffs_checkpt_dev_to_dev(dev, &cp);
354 
355 	n_bytes = n_blocks * sizeof(struct yaffs_block_info);
356 
357 	ok = (yaffs2_checkpt_rd(dev, dev->block_info, n_bytes) == n_bytes);
358 
359 	if (!ok)
360 		return 0;
361 
362 	n_bytes = n_blocks * dev->chunk_bit_stride;
363 
364 	ok = (yaffs2_checkpt_rd(dev, dev->chunk_bits, n_bytes) == n_bytes);
365 
366 	return ok ? 1 : 0;
367 }
368 
yaffs2_obj_checkpt_obj(struct yaffs_checkpt_obj * cp,struct yaffs_obj * obj)369 static void yaffs2_obj_checkpt_obj(struct yaffs_checkpt_obj *cp,
370 				   struct yaffs_obj *obj)
371 {
372 	cp->obj_id = obj->obj_id;
373 	cp->parent_id = (obj->parent) ? obj->parent->obj_id : 0;
374 	cp->hdr_chunk = obj->hdr_chunk;
375 	cp->variant_type = obj->variant_type;
376 	cp->deleted = obj->deleted;
377 	cp->soft_del = obj->soft_del;
378 	cp->unlinked = obj->unlinked;
379 	cp->fake = obj->fake;
380 	cp->rename_allowed = obj->rename_allowed;
381 	cp->unlink_allowed = obj->unlink_allowed;
382 	cp->serial = obj->serial;
383 	cp->n_data_chunks = obj->n_data_chunks;
384 
385 	if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
386 		cp->size_or_equiv_obj = obj->variant.file_variant.file_size;
387 	else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
388 		cp->size_or_equiv_obj = obj->variant.hardlink_variant.equiv_id;
389 }
390 
yaffs2_checkpt_obj_to_obj(struct yaffs_obj * obj,struct yaffs_checkpt_obj * cp)391 static int yaffs2_checkpt_obj_to_obj(struct yaffs_obj *obj,
392 				     struct yaffs_checkpt_obj *cp)
393 {
394 	struct yaffs_obj *parent;
395 
396 	if (obj->variant_type != cp->variant_type) {
397 		yaffs_trace(YAFFS_TRACE_ERROR,
398 			"Checkpoint read object %d type %d chunk %d does not match existing object type %d",
399 			cp->obj_id, cp->variant_type, cp->hdr_chunk,
400 			obj->variant_type);
401 		return 0;
402 	}
403 
404 	obj->obj_id = cp->obj_id;
405 
406 	if (cp->parent_id)
407 		parent = yaffs_find_or_create_by_number(obj->my_dev,
408 						cp->parent_id,
409 						YAFFS_OBJECT_TYPE_DIRECTORY);
410 	else
411 		parent = NULL;
412 
413 	if (parent) {
414 		if (parent->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
415 			yaffs_trace(YAFFS_TRACE_ALWAYS,
416 				"Checkpoint read object %d parent %d type %d chunk %d Parent type, %d, not directory",
417 				cp->obj_id, cp->parent_id,
418 				cp->variant_type, cp->hdr_chunk,
419 				parent->variant_type);
420 			return 0;
421 		}
422 		yaffs_add_obj_to_dir(parent, obj);
423 	}
424 
425 	obj->hdr_chunk = cp->hdr_chunk;
426 	obj->variant_type = cp->variant_type;
427 	obj->deleted = cp->deleted;
428 	obj->soft_del = cp->soft_del;
429 	obj->unlinked = cp->unlinked;
430 	obj->fake = cp->fake;
431 	obj->rename_allowed = cp->rename_allowed;
432 	obj->unlink_allowed = cp->unlink_allowed;
433 	obj->serial = cp->serial;
434 	obj->n_data_chunks = cp->n_data_chunks;
435 
436 	if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
437 		obj->variant.file_variant.file_size = cp->size_or_equiv_obj;
438 	else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
439 		obj->variant.hardlink_variant.equiv_id = cp->size_or_equiv_obj;
440 
441 	if (obj->hdr_chunk > 0)
442 		obj->lazy_loaded = 1;
443 	return 1;
444 }
445 
yaffs2_checkpt_tnode_worker(struct yaffs_obj * in,struct yaffs_tnode * tn,u32 level,int chunk_offset)446 static int yaffs2_checkpt_tnode_worker(struct yaffs_obj *in,
447 				       struct yaffs_tnode *tn, u32 level,
448 				       int chunk_offset)
449 {
450 	int i;
451 	struct yaffs_dev *dev = in->my_dev;
452 	int ok = 1;
453 	u32 base_offset;
454 
455 	if (!tn)
456 		return 1;
457 
458 	if (level > 0) {
459 		for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++) {
460 			if (!tn->internal[i])
461 				continue;
462 			ok = yaffs2_checkpt_tnode_worker(in,
463 				 tn->internal[i],
464 				 level - 1,
465 				 (chunk_offset <<
466 				  YAFFS_TNODES_INTERNAL_BITS) + i);
467 		}
468 		return ok;
469 	}
470 
471 	/* Level 0 tnode */
472 	base_offset = chunk_offset << YAFFS_TNODES_LEVEL0_BITS;
473 	ok = (yaffs2_checkpt_wr(dev, &base_offset, sizeof(base_offset)) ==
474 			sizeof(base_offset));
475 	if (ok)
476 		ok = (yaffs2_checkpt_wr(dev, tn, dev->tnode_size) ==
477 			dev->tnode_size);
478 
479 	return ok;
480 }
481 
yaffs2_wr_checkpt_tnodes(struct yaffs_obj * obj)482 static int yaffs2_wr_checkpt_tnodes(struct yaffs_obj *obj)
483 {
484 	u32 end_marker = ~0;
485 	int ok = 1;
486 
487 	if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
488 		return ok;
489 
490 	ok = yaffs2_checkpt_tnode_worker(obj,
491 					 obj->variant.file_variant.top,
492 					 obj->variant.file_variant.
493 					 top_level, 0);
494 	if (ok)
495 		ok = (yaffs2_checkpt_wr(obj->my_dev, &end_marker,
496 				sizeof(end_marker)) == sizeof(end_marker));
497 
498 	return ok ? 1 : 0;
499 }
500 
yaffs2_rd_checkpt_tnodes(struct yaffs_obj * obj)501 static int yaffs2_rd_checkpt_tnodes(struct yaffs_obj *obj)
502 {
503 	u32 base_chunk;
504 	int ok = 1;
505 	struct yaffs_dev *dev = obj->my_dev;
506 	struct yaffs_file_var *file_stuct_ptr = &obj->variant.file_variant;
507 	struct yaffs_tnode *tn;
508 	int nread = 0;
509 
510 	ok = (yaffs2_checkpt_rd(dev, &base_chunk, sizeof(base_chunk)) ==
511 	      sizeof(base_chunk));
512 
513 	while (ok && (~base_chunk)) {
514 		nread++;
515 		/* Read level 0 tnode */
516 
517 		tn = yaffs_get_tnode(dev);
518 		if (tn)
519 			ok = (yaffs2_checkpt_rd(dev, tn, dev->tnode_size) ==
520 				dev->tnode_size);
521 		else
522 			ok = 0;
523 
524 		if (tn && ok)
525 			ok = yaffs_add_find_tnode_0(dev,
526 						    file_stuct_ptr,
527 						    base_chunk, tn) ? 1 : 0;
528 
529 		if (ok)
530 			ok = (yaffs2_checkpt_rd
531 			      (dev, &base_chunk,
532 			       sizeof(base_chunk)) == sizeof(base_chunk));
533 	}
534 
535 	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
536 		"Checkpoint read tnodes %d records, last %d. ok %d",
537 		nread, base_chunk, ok);
538 
539 	return ok ? 1 : 0;
540 }
541 
yaffs2_wr_checkpt_objs(struct yaffs_dev * dev)542 static int yaffs2_wr_checkpt_objs(struct yaffs_dev *dev)
543 {
544 	struct yaffs_obj *obj;
545 	struct yaffs_checkpt_obj cp;
546 	int i;
547 	int ok = 1;
548 	struct list_head *lh;
549 
550 	/* Iterate through the objects in each hash entry,
551 	 * dumping them to the checkpointing stream.
552 	 */
553 
554 	for (i = 0; ok && i < YAFFS_NOBJECT_BUCKETS; i++) {
555 		list_for_each(lh, &dev->obj_bucket[i].list) {
556 			obj = list_entry(lh, struct yaffs_obj, hash_link);
557 			if (!obj->defered_free) {
558 				yaffs2_obj_checkpt_obj(&cp, obj);
559 				cp.struct_type = sizeof(cp);
560 
561 				yaffs_trace(YAFFS_TRACE_CHECKPOINT,
562 					"Checkpoint write object %d parent %d type %d chunk %d obj addr %p",
563 					cp.obj_id, cp.parent_id,
564 					cp.variant_type, cp.hdr_chunk, obj);
565 
566 				ok = (yaffs2_checkpt_wr(dev, &cp,
567 						sizeof(cp)) == sizeof(cp));
568 
569 				if (ok &&
570 					obj->variant_type ==
571 					YAFFS_OBJECT_TYPE_FILE)
572 					ok = yaffs2_wr_checkpt_tnodes(obj);
573 			}
574 		}
575 	}
576 
577 	/* Dump end of list */
578 	memset(&cp, 0xff, sizeof(struct yaffs_checkpt_obj));
579 	cp.struct_type = sizeof(cp);
580 
581 	if (ok)
582 		ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
583 
584 	return ok ? 1 : 0;
585 }
586 
yaffs2_rd_checkpt_objs(struct yaffs_dev * dev)587 static int yaffs2_rd_checkpt_objs(struct yaffs_dev *dev)
588 {
589 	struct yaffs_obj *obj;
590 	struct yaffs_checkpt_obj cp;
591 	int ok = 1;
592 	int done = 0;
593 	LIST_HEAD(hard_list);
594 
595 
596 	while (ok && !done) {
597 		ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
598 		if (cp.struct_type != sizeof(cp)) {
599 			yaffs_trace(YAFFS_TRACE_CHECKPOINT,
600 				"struct size %d instead of %d ok %d",
601 				cp.struct_type, (int)sizeof(cp), ok);
602 			ok = 0;
603 		}
604 
605 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
606 			"Checkpoint read object %d parent %d type %d chunk %d ",
607 			cp.obj_id, cp.parent_id, cp.variant_type,
608 			cp.hdr_chunk);
609 
610 		if (ok && cp.obj_id == ~0) {
611 			done = 1;
612 		} else if (ok) {
613 			obj =
614 			    yaffs_find_or_create_by_number(dev, cp.obj_id,
615 							   cp.variant_type);
616 			if (obj) {
617 				ok = yaffs2_checkpt_obj_to_obj(obj, &cp);
618 				if (!ok)
619 					break;
620 				if (obj->variant_type ==
621 					YAFFS_OBJECT_TYPE_FILE) {
622 					ok = yaffs2_rd_checkpt_tnodes(obj);
623 				} else if (obj->variant_type ==
624 					YAFFS_OBJECT_TYPE_HARDLINK) {
625 					list_add(&obj->hard_links, &hard_list);
626 				}
627 			} else {
628 				ok = 0;
629 			}
630 		}
631 	}
632 
633 	if (ok)
634 		yaffs_link_fixup(dev, &hard_list);
635 
636 	return ok ? 1 : 0;
637 }
638 
yaffs2_wr_checkpt_sum(struct yaffs_dev * dev)639 static int yaffs2_wr_checkpt_sum(struct yaffs_dev *dev)
640 {
641 	u32 checkpt_sum;
642 	int ok;
643 
644 	yaffs2_get_checkpt_sum(dev, &checkpt_sum);
645 
646 	ok = (yaffs2_checkpt_wr(dev, &checkpt_sum, sizeof(checkpt_sum)) ==
647 		sizeof(checkpt_sum));
648 
649 	if (!ok)
650 		return 0;
651 
652 	return 1;
653 }
654 
yaffs2_rd_checkpt_sum(struct yaffs_dev * dev)655 static int yaffs2_rd_checkpt_sum(struct yaffs_dev *dev)
656 {
657 	u32 checkpt_sum0;
658 	u32 checkpt_sum1;
659 	int ok;
660 
661 	yaffs2_get_checkpt_sum(dev, &checkpt_sum0);
662 
663 	ok = (yaffs2_checkpt_rd(dev, &checkpt_sum1, sizeof(checkpt_sum1)) ==
664 		sizeof(checkpt_sum1));
665 
666 	if (!ok)
667 		return 0;
668 
669 	if (checkpt_sum0 != checkpt_sum1)
670 		return 0;
671 
672 	return 1;
673 }
674 
yaffs2_wr_checkpt_data(struct yaffs_dev * dev)675 static int yaffs2_wr_checkpt_data(struct yaffs_dev *dev)
676 {
677 	int ok = 1;
678 
679 	if (!yaffs2_checkpt_required(dev)) {
680 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
681 			"skipping checkpoint write");
682 		ok = 0;
683 	}
684 
685 	if (ok)
686 		ok = yaffs2_checkpt_open(dev, 1);
687 
688 	if (ok) {
689 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
690 			"write checkpoint validity");
691 		ok = yaffs2_wr_checkpt_validity_marker(dev, 1);
692 	}
693 	if (ok) {
694 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
695 			"write checkpoint device");
696 		ok = yaffs2_wr_checkpt_dev(dev);
697 	}
698 	if (ok) {
699 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
700 			"write checkpoint objects");
701 		ok = yaffs2_wr_checkpt_objs(dev);
702 	}
703 	if (ok) {
704 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
705 			"write checkpoint validity");
706 		ok = yaffs2_wr_checkpt_validity_marker(dev, 0);
707 	}
708 
709 	if (ok)
710 		ok = yaffs2_wr_checkpt_sum(dev);
711 
712 	if (!yaffs_checkpt_close(dev))
713 		ok = 0;
714 
715 	if (ok)
716 		dev->is_checkpointed = 1;
717 	else
718 		dev->is_checkpointed = 0;
719 
720 	return dev->is_checkpointed;
721 }
722 
yaffs2_rd_checkpt_data(struct yaffs_dev * dev)723 static int yaffs2_rd_checkpt_data(struct yaffs_dev *dev)
724 {
725 	int ok = 1;
726 
727 	if (!dev->param.is_yaffs2)
728 		ok = 0;
729 
730 	if (ok && dev->param.skip_checkpt_rd) {
731 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
732 			"skipping checkpoint read");
733 		ok = 0;
734 	}
735 
736 	if (ok)
737 		ok = yaffs2_checkpt_open(dev, 0); /* open for read */
738 
739 	if (ok) {
740 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
741 			"read checkpoint validity");
742 		ok = yaffs2_rd_checkpt_validity_marker(dev, 1);
743 	}
744 	if (ok) {
745 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
746 			"read checkpoint device");
747 		ok = yaffs2_rd_checkpt_dev(dev);
748 	}
749 	if (ok) {
750 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
751 			"read checkpoint objects");
752 		ok = yaffs2_rd_checkpt_objs(dev);
753 	}
754 	if (ok) {
755 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
756 			"read checkpoint validity");
757 		ok = yaffs2_rd_checkpt_validity_marker(dev, 0);
758 	}
759 
760 	if (ok) {
761 		ok = yaffs2_rd_checkpt_sum(dev);
762 		yaffs_trace(YAFFS_TRACE_CHECKPOINT,
763 			"read checkpoint checksum %d", ok);
764 	}
765 
766 	if (!yaffs_checkpt_close(dev))
767 		ok = 0;
768 
769 	if (ok)
770 		dev->is_checkpointed = 1;
771 	else
772 		dev->is_checkpointed = 0;
773 
774 	return ok ? 1 : 0;
775 }
776 
yaffs2_checkpt_invalidate(struct yaffs_dev * dev)777 void yaffs2_checkpt_invalidate(struct yaffs_dev *dev)
778 {
779 	if (dev->is_checkpointed || dev->blocks_in_checkpt > 0) {
780 		dev->is_checkpointed = 0;
781 		yaffs2_checkpt_invalidate_stream(dev);
782 	}
783 	if (dev->param.sb_dirty_fn)
784 		dev->param.sb_dirty_fn(dev);
785 }
786 
yaffs_checkpoint_save(struct yaffs_dev * dev)787 int yaffs_checkpoint_save(struct yaffs_dev *dev)
788 {
789 	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
790 		"save entry: is_checkpointed %d",
791 		dev->is_checkpointed);
792 
793 	yaffs_verify_objects(dev);
794 	yaffs_verify_blocks(dev);
795 	yaffs_verify_free_chunks(dev);
796 
797 	if (!dev->is_checkpointed) {
798 		yaffs2_checkpt_invalidate(dev);
799 		yaffs2_wr_checkpt_data(dev);
800 	}
801 
802 	yaffs_trace(YAFFS_TRACE_CHECKPOINT | YAFFS_TRACE_MOUNT,
803 		"save exit: is_checkpointed %d",
804 		dev->is_checkpointed);
805 
806 	return dev->is_checkpointed;
807 }
808 
yaffs2_checkpt_restore(struct yaffs_dev * dev)809 int yaffs2_checkpt_restore(struct yaffs_dev *dev)
810 {
811 	int retval;
812 
813 	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
814 		"restore entry: is_checkpointed %d",
815 		dev->is_checkpointed);
816 
817 	retval = yaffs2_rd_checkpt_data(dev);
818 
819 	if (dev->is_checkpointed) {
820 		yaffs_verify_objects(dev);
821 		yaffs_verify_blocks(dev);
822 		yaffs_verify_free_chunks(dev);
823 	}
824 
825 	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
826 		"restore exit: is_checkpointed %d",
827 		dev->is_checkpointed);
828 
829 	return retval;
830 }
831 
yaffs2_handle_hole(struct yaffs_obj * obj,loff_t new_size)832 int yaffs2_handle_hole(struct yaffs_obj *obj, loff_t new_size)
833 {
834 	/* if new_size > old_file_size.
835 	 * We're going to be writing a hole.
836 	 * If the hole is small then write zeros otherwise write a start
837 	 * of hole marker.
838 	 */
839 	loff_t old_file_size;
840 	loff_t increase;
841 	int small_hole;
842 	int result = YAFFS_OK;
843 	struct yaffs_dev *dev = NULL;
844 	u8 *local_buffer = NULL;
845 	int small_increase_ok = 0;
846 
847 	if (!obj)
848 		return YAFFS_FAIL;
849 
850 	if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
851 		return YAFFS_FAIL;
852 
853 	dev = obj->my_dev;
854 
855 	/* Bail out if not yaffs2 mode */
856 	if (!dev->param.is_yaffs2)
857 		return YAFFS_OK;
858 
859 	old_file_size = obj->variant.file_variant.file_size;
860 
861 	if (new_size <= old_file_size)
862 		return YAFFS_OK;
863 
864 	increase = new_size - old_file_size;
865 
866 	if (increase < YAFFS_SMALL_HOLE_THRESHOLD * dev->data_bytes_per_chunk &&
867 	    yaffs_check_alloc_available(dev, YAFFS_SMALL_HOLE_THRESHOLD + 1))
868 		small_hole = 1;
869 	else
870 		small_hole = 0;
871 
872 	if (small_hole)
873 		local_buffer = yaffs_get_temp_buffer(dev);
874 
875 	if (local_buffer) {
876 		/* fill hole with zero bytes */
877 		loff_t pos = old_file_size;
878 		int this_write;
879 		int written;
880 		memset(local_buffer, 0, dev->data_bytes_per_chunk);
881 		small_increase_ok = 1;
882 
883 		while (increase > 0 && small_increase_ok) {
884 			this_write = increase;
885 			if (this_write > dev->data_bytes_per_chunk)
886 				this_write = dev->data_bytes_per_chunk;
887 			written =
888 			    yaffs_do_file_wr(obj, local_buffer, pos, this_write,
889 					     0);
890 			if (written == this_write) {
891 				pos += this_write;
892 				increase -= this_write;
893 			} else {
894 				small_increase_ok = 0;
895 			}
896 		}
897 
898 		yaffs_release_temp_buffer(dev, local_buffer);
899 
900 		/* If out of space then reverse any chunks we've added */
901 		if (!small_increase_ok)
902 			yaffs_resize_file_down(obj, old_file_size);
903 	}
904 
905 	if (!small_increase_ok &&
906 	    obj->parent &&
907 	    obj->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
908 	    obj->parent->obj_id != YAFFS_OBJECTID_DELETED) {
909 		/* Write a hole start header with the old file size */
910 		yaffs_update_oh(obj, NULL, 0, 1, 0, NULL);
911 	}
912 
913 	return result;
914 }
915 
916 struct yaffs_block_index {
917 	int seq;
918 	int block;
919 };
920 
yaffs2_ybicmp(const void * a,const void * b)921 static int yaffs2_ybicmp(const void *a, const void *b)
922 {
923 	int aseq = ((struct yaffs_block_index *)a)->seq;
924 	int bseq = ((struct yaffs_block_index *)b)->seq;
925 	int ablock = ((struct yaffs_block_index *)a)->block;
926 	int bblock = ((struct yaffs_block_index *)b)->block;
927 
928 	if (aseq == bseq)
929 		return ablock - bblock;
930 
931 	return aseq - bseq;
932 }
933 
yaffs2_scan_chunk(struct yaffs_dev * dev,struct yaffs_block_info * bi,int blk,int chunk_in_block,int * found_chunks,u8 * chunk_data,struct list_head * hard_list,int summary_available)934 static inline int yaffs2_scan_chunk(struct yaffs_dev *dev,
935 		struct yaffs_block_info *bi,
936 		int blk, int chunk_in_block,
937 		int *found_chunks,
938 		u8 *chunk_data,
939 		struct list_head *hard_list,
940 		int summary_available)
941 {
942 	struct yaffs_obj_hdr *oh;
943 	struct yaffs_obj *in;
944 	struct yaffs_obj *parent;
945 	int equiv_id;
946 	loff_t file_size;
947 	int is_shrink;
948 	int is_unlinked;
949 	struct yaffs_ext_tags tags;
950 	int alloc_failed = 0;
951 	int chunk = blk * dev->param.chunks_per_block + chunk_in_block;
952 	struct yaffs_file_var *file_var;
953 	struct yaffs_hardlink_var *hl_var;
954 	struct yaffs_symlink_var *sl_var;
955 
956 	if (summary_available) {
957 		yaffs_summary_fetch(dev, &tags, chunk_in_block);
958 		tags.seq_number = bi->seq_number;
959 	}
960 
961 	if (!summary_available || tags.obj_id == 0) {
962 		yaffs_rd_chunk_tags_nand(dev, chunk, NULL, &tags);
963 		dev->tags_used++;
964 	} else {
965 		dev->summary_used++;
966 	}
967 
968 	/* Let's have a good look at this chunk... */
969 
970 	if (!tags.chunk_used) {
971 		/* An unassigned chunk in the block.
972 		 * If there are used chunks after this one, then
973 		 * it is a chunk that was skipped due to failing
974 		 * the erased check. Just skip it so that it can
975 		 * be deleted.
976 		 * But, more typically, We get here when this is
977 		 * an unallocated chunk and his means that
978 		 * either the block is empty or this is the one
979 		 * being allocated from
980 		 */
981 
982 		if (*found_chunks) {
983 			/* This is a chunk that was skipped due
984 			 * to failing the erased check */
985 		} else if (chunk_in_block == 0) {
986 			/* We're looking at the first chunk in
987 			 * the block so the block is unused */
988 			bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
989 			dev->n_erased_blocks++;
990 		} else {
991 			if (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
992 			    bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
993 				if (dev->seq_number == bi->seq_number) {
994 					/* Allocating from this block*/
995 					yaffs_trace(YAFFS_TRACE_SCAN,
996 					    " Allocating from %d %d",
997 					    blk, chunk_in_block);
998 
999 					bi->block_state =
1000 						YAFFS_BLOCK_STATE_ALLOCATING;
1001 					dev->alloc_block = blk;
1002 					dev->alloc_page = chunk_in_block;
1003 					dev->alloc_block_finder = blk;
1004 				} else {
1005 					/* This is a partially written block
1006 					 * that is not the current
1007 					 * allocation block.
1008 					 */
1009 					yaffs_trace(YAFFS_TRACE_SCAN,
1010 						"Partially written block %d detected. gc will fix this.",
1011 						blk);
1012 				}
1013 			}
1014 		}
1015 
1016 		dev->n_free_chunks++;
1017 
1018 	} else if (tags.ecc_result ==
1019 		YAFFS_ECC_RESULT_UNFIXED) {
1020 		yaffs_trace(YAFFS_TRACE_SCAN,
1021 			" Unfixed ECC in chunk(%d:%d), chunk ignored",
1022 			blk, chunk_in_block);
1023 			dev->n_free_chunks++;
1024 	} else if (tags.obj_id > YAFFS_MAX_OBJECT_ID ||
1025 		   tags.chunk_id > YAFFS_MAX_CHUNK_ID ||
1026 		   tags.obj_id == YAFFS_OBJECTID_SUMMARY ||
1027 		   (tags.chunk_id > 0 &&
1028 		     tags.n_bytes > dev->data_bytes_per_chunk) ||
1029 		   tags.seq_number != bi->seq_number) {
1030 		yaffs_trace(YAFFS_TRACE_SCAN,
1031 			"Chunk (%d:%d) with bad tags:obj = %d, chunk_id = %d, n_bytes = %d, ignored",
1032 			blk, chunk_in_block, tags.obj_id,
1033 			tags.chunk_id, tags.n_bytes);
1034 		dev->n_free_chunks++;
1035 	} else if (tags.chunk_id > 0) {
1036 		/* chunk_id > 0 so it is a data chunk... */
1037 		loff_t endpos;
1038 		loff_t chunk_base = (tags.chunk_id - 1) *
1039 					dev->data_bytes_per_chunk;
1040 
1041 		*found_chunks = 1;
1042 
1043 		yaffs_set_chunk_bit(dev, blk, chunk_in_block);
1044 		bi->pages_in_use++;
1045 
1046 		in = yaffs_find_or_create_by_number(dev,
1047 					tags.obj_id,
1048 					YAFFS_OBJECT_TYPE_FILE);
1049 		if (!in)
1050 			/* Out of memory */
1051 			alloc_failed = 1;
1052 
1053 		if (in &&
1054 		    in->variant_type == YAFFS_OBJECT_TYPE_FILE &&
1055 		    chunk_base < in->variant.file_variant.shrink_size) {
1056 			/* This has not been invalidated by
1057 			 * a resize */
1058 			if (!yaffs_put_chunk_in_file(in, tags.chunk_id,
1059 								chunk, -1))
1060 				alloc_failed = 1;
1061 
1062 			/* File size is calculated by looking at
1063 			 * the data chunks if we have not
1064 			 * seen an object header yet.
1065 			 * Stop this practice once we find an
1066 			 * object header.
1067 			 */
1068 			endpos = chunk_base + tags.n_bytes;
1069 
1070 			if (!in->valid &&
1071 			    in->variant.file_variant.scanned_size < endpos) {
1072 				in->variant.file_variant.
1073 				    scanned_size = endpos;
1074 				in->variant.file_variant.
1075 				    file_size = endpos;
1076 			}
1077 		} else if (in) {
1078 			/* This chunk has been invalidated by a
1079 			 * resize, or a past file deletion
1080 			 * so delete the chunk*/
1081 			yaffs_chunk_del(dev, chunk, 1, __LINE__);
1082 		}
1083 	} else {
1084 		/* chunk_id == 0, so it is an ObjectHeader.
1085 		 * Thus, we read in the object header and make
1086 		 * the object
1087 		 */
1088 		*found_chunks = 1;
1089 
1090 		yaffs_set_chunk_bit(dev, blk, chunk_in_block);
1091 		bi->pages_in_use++;
1092 
1093 		oh = NULL;
1094 		in = NULL;
1095 
1096 		if (tags.extra_available) {
1097 			in = yaffs_find_or_create_by_number(dev,
1098 					tags.obj_id,
1099 					tags.extra_obj_type);
1100 			if (!in)
1101 				alloc_failed = 1;
1102 		}
1103 
1104 		if (!in ||
1105 		    (!in->valid && dev->param.disable_lazy_load) ||
1106 		    tags.extra_shadows ||
1107 		    (!in->valid && (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1108 				 tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND))) {
1109 
1110 			/* If we don't have  valid info then we
1111 			 * need to read the chunk
1112 			 * TODO In future we can probably defer
1113 			 * reading the chunk and living with
1114 			 * invalid data until needed.
1115 			 */
1116 
1117 			yaffs_rd_chunk_tags_nand(dev, chunk, chunk_data, NULL);
1118 
1119 			oh = (struct yaffs_obj_hdr *)chunk_data;
1120 
1121 			if (dev->param.inband_tags) {
1122 				/* Fix up the header if they got
1123 				 * corrupted by inband tags */
1124 				oh->shadows_obj =
1125 				    oh->inband_shadowed_obj_id;
1126 				oh->is_shrink =
1127 				    oh->inband_is_shrink;
1128 			}
1129 
1130 			if (!in) {
1131 				in = yaffs_find_or_create_by_number(dev,
1132 							tags.obj_id, oh->type);
1133 				if (!in)
1134 					alloc_failed = 1;
1135 			}
1136 		}
1137 
1138 		if (!in) {
1139 			/* TODO Hoosterman we have a problem! */
1140 			yaffs_trace(YAFFS_TRACE_ERROR,
1141 				"yaffs tragedy: Could not make object for object  %d at chunk %d during scan",
1142 				tags.obj_id, chunk);
1143 			return YAFFS_FAIL;
1144 		}
1145 
1146 		if (in->valid) {
1147 			/* We have already filled this one.
1148 			 * We have a duplicate that will be
1149 			 * discarded, but we first have to suck
1150 			 * out resize info if it is a file.
1151 			 */
1152 			if ((in->variant_type == YAFFS_OBJECT_TYPE_FILE) &&
1153 				((oh && oh->type == YAFFS_OBJECT_TYPE_FILE) ||
1154 				 (tags.extra_available &&
1155 				  tags.extra_obj_type == YAFFS_OBJECT_TYPE_FILE)
1156 				)) {
1157 				loff_t this_size = (oh) ?
1158 					yaffs_oh_to_size(oh) :
1159 					tags.extra_file_size;
1160 				u32 parent_obj_id = (oh) ?
1161 					oh->parent_obj_id :
1162 					tags.extra_parent_id;
1163 
1164 				is_shrink = (oh) ?
1165 					oh->is_shrink :
1166 					tags.extra_is_shrink;
1167 
1168 				/* If it is deleted (unlinked
1169 				 * at start also means deleted)
1170 				 * we treat the file size as
1171 				 * being zeroed at this point.
1172 				 */
1173 				if (parent_obj_id == YAFFS_OBJECTID_DELETED ||
1174 				    parent_obj_id == YAFFS_OBJECTID_UNLINKED) {
1175 					this_size = 0;
1176 					is_shrink = 1;
1177 				}
1178 
1179 				if (is_shrink &&
1180 				    in->variant.file_variant.shrink_size >
1181 				    this_size)
1182 					in->variant.file_variant.shrink_size =
1183 					this_size;
1184 
1185 				if (is_shrink)
1186 					bi->has_shrink_hdr = 1;
1187 			}
1188 			/* Use existing - destroy this one. */
1189 			yaffs_chunk_del(dev, chunk, 1, __LINE__);
1190 		}
1191 
1192 		if (!in->valid && in->variant_type !=
1193 		    (oh ? oh->type : tags.extra_obj_type))
1194 			yaffs_trace(YAFFS_TRACE_ERROR,
1195 				"yaffs tragedy: Bad object type, %d != %d, for object %d at chunk %d during scan",
1196 				oh ? oh->type : tags.extra_obj_type,
1197 				in->variant_type, tags.obj_id,
1198 				chunk);
1199 
1200 		if (!in->valid &&
1201 		    (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1202 		     tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND)) {
1203 			/* We only load some info, don't fiddle
1204 			 * with directory structure */
1205 			in->valid = 1;
1206 
1207 			if (oh) {
1208 				in->yst_mode = oh->yst_mode;
1209 				yaffs_load_attribs(in, oh);
1210 				in->lazy_loaded = 0;
1211 			} else {
1212 				in->lazy_loaded = 1;
1213 			}
1214 			in->hdr_chunk = chunk;
1215 
1216 		} else if (!in->valid) {
1217 			/* we need to load this info */
1218 			in->valid = 1;
1219 			in->hdr_chunk = chunk;
1220 			if (oh) {
1221 				in->variant_type = oh->type;
1222 				in->yst_mode = oh->yst_mode;
1223 				yaffs_load_attribs(in, oh);
1224 
1225 				if (oh->shadows_obj > 0)
1226 					yaffs_handle_shadowed_obj(dev,
1227 					     oh->shadows_obj, 1);
1228 
1229 				yaffs_set_obj_name_from_oh(in, oh);
1230 				parent = yaffs_find_or_create_by_number(dev,
1231 						oh->parent_obj_id,
1232 						YAFFS_OBJECT_TYPE_DIRECTORY);
1233 				file_size = yaffs_oh_to_size(oh);
1234 				is_shrink = oh->is_shrink;
1235 				equiv_id = oh->equiv_id;
1236 			} else {
1237 				in->variant_type = tags.extra_obj_type;
1238 				parent = yaffs_find_or_create_by_number(dev,
1239 						tags.extra_parent_id,
1240 						YAFFS_OBJECT_TYPE_DIRECTORY);
1241 				file_size = tags.extra_file_size;
1242 				is_shrink = tags.extra_is_shrink;
1243 				equiv_id = tags.extra_equiv_id;
1244 				in->lazy_loaded = 1;
1245 			}
1246 			in->dirty = 0;
1247 
1248 			if (!parent)
1249 				alloc_failed = 1;
1250 
1251 			/* directory stuff...
1252 			 * hook up to parent
1253 			 */
1254 
1255 			if (parent &&
1256 			    parent->variant_type == YAFFS_OBJECT_TYPE_UNKNOWN) {
1257 				/* Set up as a directory */
1258 				parent->variant_type =
1259 					YAFFS_OBJECT_TYPE_DIRECTORY;
1260 				INIT_LIST_HEAD(&parent->
1261 						variant.dir_variant.children);
1262 			} else if (!parent ||
1263 				   parent->variant_type !=
1264 					YAFFS_OBJECT_TYPE_DIRECTORY) {
1265 				/* Hoosterman, another problem....
1266 				 * Trying to use a non-directory as a directory
1267 				 */
1268 
1269 				yaffs_trace(YAFFS_TRACE_ERROR,
1270 					"yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
1271 					);
1272 				parent = dev->lost_n_found;
1273 			}
1274 			yaffs_add_obj_to_dir(parent, in);
1275 
1276 			is_unlinked = (parent == dev->del_dir) ||
1277 					(parent == dev->unlinked_dir);
1278 
1279 			if (is_shrink)
1280 				/* Mark the block */
1281 				bi->has_shrink_hdr = 1;
1282 
1283 			/* Note re hardlinks.
1284 			 * Since we might scan a hardlink before its equivalent
1285 			 * object is scanned we put them all in a list.
1286 			 * After scanning is complete, we should have all the
1287 			 * objects, so we run through this list and fix up all
1288 			 * the chains.
1289 			 */
1290 
1291 			switch (in->variant_type) {
1292 			case YAFFS_OBJECT_TYPE_UNKNOWN:
1293 				/* Todo got a problem */
1294 				break;
1295 			case YAFFS_OBJECT_TYPE_FILE:
1296 				file_var = &in->variant.file_variant;
1297 				if (file_var->scanned_size < file_size) {
1298 					/* This covers the case where the file
1299 					 * size is greater than the data held.
1300 					 * This will happen if the file is
1301 					 * resized to be larger than its
1302 					 * current data extents.
1303 					 */
1304 					file_var->file_size = file_size;
1305 					file_var->scanned_size = file_size;
1306 				}
1307 
1308 				if (file_var->shrink_size > file_size)
1309 					file_var->shrink_size = file_size;
1310 
1311 				break;
1312 			case YAFFS_OBJECT_TYPE_HARDLINK:
1313 				hl_var = &in->variant.hardlink_variant;
1314 				if (!is_unlinked) {
1315 					hl_var->equiv_id = equiv_id;
1316 					list_add(&in->hard_links, hard_list);
1317 				}
1318 				break;
1319 			case YAFFS_OBJECT_TYPE_DIRECTORY:
1320 				/* Do nothing */
1321 				break;
1322 			case YAFFS_OBJECT_TYPE_SPECIAL:
1323 				/* Do nothing */
1324 				break;
1325 			case YAFFS_OBJECT_TYPE_SYMLINK:
1326 				sl_var = &in->variant.symlink_variant;
1327 				if (oh) {
1328 					sl_var->alias =
1329 					    yaffs_clone_str(oh->alias);
1330 					if (!sl_var->alias)
1331 						alloc_failed = 1;
1332 				}
1333 				break;
1334 			}
1335 		}
1336 	}
1337 	return alloc_failed ? YAFFS_FAIL : YAFFS_OK;
1338 }
1339 
yaffs2_scan_backwards(struct yaffs_dev * dev)1340 int yaffs2_scan_backwards(struct yaffs_dev *dev)
1341 {
1342 	int blk;
1343 	int block_iter;
1344 	int start_iter;
1345 	int end_iter;
1346 	int n_to_scan = 0;
1347 	enum yaffs_block_state state;
1348 	int c;
1349 	LIST_HEAD(hard_list);
1350 	struct yaffs_block_info *bi;
1351 	u32 seq_number;
1352 	int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
1353 	u8 *chunk_data;
1354 	int found_chunks;
1355 	int alloc_failed = 0;
1356 	struct yaffs_block_index *block_index = NULL;
1357 	int alt_block_index = 0;
1358 	int summary_available;
1359 
1360 	yaffs_trace(YAFFS_TRACE_SCAN,
1361 		"yaffs2_scan_backwards starts  intstartblk %d intendblk %d...",
1362 		dev->internal_start_block, dev->internal_end_block);
1363 
1364 	dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
1365 
1366 	block_index =
1367 		kmalloc(n_blocks * sizeof(struct yaffs_block_index), GFP_NOFS);
1368 
1369 	if (!block_index) {
1370 		block_index =
1371 		    vmalloc(n_blocks * sizeof(struct yaffs_block_index));
1372 		alt_block_index = 1;
1373 	}
1374 
1375 	if (!block_index) {
1376 		yaffs_trace(YAFFS_TRACE_SCAN,
1377 			"yaffs2_scan_backwards() could not allocate block index!"
1378 			);
1379 		return YAFFS_FAIL;
1380 	}
1381 
1382 	dev->blocks_in_checkpt = 0;
1383 
1384 	chunk_data = yaffs_get_temp_buffer(dev);
1385 
1386 	/* Scan all the blocks to determine their state */
1387 	bi = dev->block_info;
1388 	for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
1389 	     blk++) {
1390 		yaffs_clear_chunk_bits(dev, blk);
1391 		bi->pages_in_use = 0;
1392 		bi->soft_del_pages = 0;
1393 
1394 		yaffs_query_init_block_state(dev, blk, &state, &seq_number);
1395 
1396 		bi->block_state = state;
1397 		bi->seq_number = seq_number;
1398 
1399 		if (bi->seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA)
1400 			bi->block_state = YAFFS_BLOCK_STATE_CHECKPOINT;
1401 		if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
1402 			bi->block_state = YAFFS_BLOCK_STATE_DEAD;
1403 
1404 		yaffs_trace(YAFFS_TRACE_SCAN_DEBUG,
1405 			"Block scanning block %d state %d seq %d",
1406 			blk, bi->block_state, seq_number);
1407 
1408 		if (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT) {
1409 			dev->blocks_in_checkpt++;
1410 
1411 		} else if (bi->block_state == YAFFS_BLOCK_STATE_DEAD) {
1412 			yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
1413 				"block %d is bad", blk);
1414 		} else if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
1415 			yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "Block empty ");
1416 			dev->n_erased_blocks++;
1417 			dev->n_free_chunks += dev->param.chunks_per_block;
1418 		} else if (bi->block_state ==
1419 				YAFFS_BLOCK_STATE_NEEDS_SCAN) {
1420 			/* Determine the highest sequence number */
1421 			if (seq_number >= YAFFS_LOWEST_SEQUENCE_NUMBER &&
1422 			    seq_number < YAFFS_HIGHEST_SEQUENCE_NUMBER) {
1423 				block_index[n_to_scan].seq = seq_number;
1424 				block_index[n_to_scan].block = blk;
1425 				n_to_scan++;
1426 				if (seq_number >= dev->seq_number)
1427 					dev->seq_number = seq_number;
1428 			} else {
1429 				/* TODO: Nasty sequence number! */
1430 				yaffs_trace(YAFFS_TRACE_SCAN,
1431 					"Block scanning block %d has bad sequence number %d",
1432 					blk, seq_number);
1433 			}
1434 		}
1435 		bi++;
1436 	}
1437 
1438 	yaffs_trace(YAFFS_TRACE_SCAN, "%d blocks to be sorted...", n_to_scan);
1439 
1440 	cond_resched();
1441 
1442 	/* Sort the blocks by sequence number */
1443 	sort(block_index, n_to_scan, sizeof(struct yaffs_block_index),
1444 		   yaffs2_ybicmp, NULL);
1445 
1446 	cond_resched();
1447 
1448 	yaffs_trace(YAFFS_TRACE_SCAN, "...done");
1449 
1450 	/* Now scan the blocks looking at the data. */
1451 	start_iter = 0;
1452 	end_iter = n_to_scan - 1;
1453 	yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "%d blocks to scan", n_to_scan);
1454 
1455 	/* For each block.... backwards */
1456 	for (block_iter = end_iter;
1457 	     !alloc_failed && block_iter >= start_iter;
1458 	     block_iter--) {
1459 		/* Cooperative multitasking! This loop can run for so
1460 		   long that watchdog timers expire. */
1461 		cond_resched();
1462 
1463 		/* get the block to scan in the correct order */
1464 		blk = block_index[block_iter].block;
1465 		bi = yaffs_get_block_info(dev, blk);
1466 
1467 		summary_available = yaffs_summary_read(dev, dev->sum_tags, blk);
1468 
1469 		/* For each chunk in each block that needs scanning.... */
1470 		found_chunks = 0;
1471 		if (summary_available)
1472 			c = dev->chunks_per_summary - 1;
1473 		else
1474 			c = dev->param.chunks_per_block - 1;
1475 
1476 		for (/* c is already initialised */;
1477 		     !alloc_failed && c >= 0 &&
1478 		     (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
1479 		      bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING);
1480 		      c--) {
1481 			/* Scan backwards...
1482 			 * Read the tags and decide what to do
1483 			 */
1484 			if (yaffs2_scan_chunk(dev, bi, blk, c,
1485 					&found_chunks, chunk_data,
1486 					&hard_list, summary_available) ==
1487 					YAFFS_FAIL)
1488 				alloc_failed = 1;
1489 		}
1490 
1491 		if (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN) {
1492 			/* If we got this far while scanning, then the block
1493 			 * is fully allocated. */
1494 			bi->block_state = YAFFS_BLOCK_STATE_FULL;
1495 		}
1496 
1497 		/* Now let's see if it was dirty */
1498 		if (bi->pages_in_use == 0 &&
1499 		    !bi->has_shrink_hdr &&
1500 		    bi->block_state == YAFFS_BLOCK_STATE_FULL) {
1501 			yaffs_block_became_dirty(dev, blk);
1502 		}
1503 	}
1504 
1505 	yaffs_skip_rest_of_block(dev);
1506 
1507 	if (alt_block_index)
1508 		vfree(block_index);
1509 	else
1510 		kfree(block_index);
1511 
1512 	/* Ok, we've done all the scanning.
1513 	 * Fix up the hard link chains.
1514 	 * We have scanned all the objects, now it's time to add these
1515 	 * hardlinks.
1516 	 */
1517 	yaffs_link_fixup(dev, &hard_list);
1518 
1519 	yaffs_release_temp_buffer(dev, chunk_data);
1520 
1521 	if (alloc_failed)
1522 		return YAFFS_FAIL;
1523 
1524 	yaffs_trace(YAFFS_TRACE_SCAN, "yaffs2_scan_backwards ends");
1525 
1526 	return YAFFS_OK;
1527 }
1528